Fibromyalgia (FM) is one of the most puzzling of the chronically painful disorders. It involves a core symptom of chronic widespread musculoskeletal pain at specific tender point (TP) sites on physical examination and is typically accompanied by fatigue, disordered sleep, cognitive complaints, an array of other somatic complaints, as well as psychological distress and significant impairments in functioning. Although largely championed and defined by rheumatologists, FM is now increasingly recognized to have a basis in central nervous system dysfunction. Treatments to date have been only partially effective and typically of modest benefit. Many persons with FM remain persistently dysfunctional and often disabled. This has given greater impetus for patients to seek complementary and alternative medicine (CAM) therapies. Within the scope of CAM, recent developments in biofeedback using electroencephalograph (EEG) or brainwave information have suggested some potential for application to FM. A novel variant of EEG biofeedback known as the Flexyx Neurotherapy System (FNS) uses very small pulses of electromagnetic energy to stimulate changes in brainwave patterns. The specific aim of this study is to evaluate the efficacy of FNS for the reduction of FM symptoms in a randomized, double-blind, placebo-controlled trial comparing two groups each of 20 patients who receive either the active intervention or a sham treatment for the same number of sessions. It is expected that immediately at the conclusion of treatment and at 3- and 6-month follow-up, patients receiving the active treatment will score significantly better on the primary outcome measure, the Fibromyalgia Impact Questionnaire total score. In terms of secondary outcome measures, it is further expected that patients receiving the active treatment will demonstrate significantly decreased heat sensitization (an objective indicator of abnormal central nervous system activity), fewer TPs and higher pressure thresholds to elicit TPs, less fatigue, improved cognitive functioning, reduced psychological distress, less depression, and improved quality of sleep. Preliminary data from this exploratory/developmental project will justify larger randomized, double-blind, placebo-controlled clinical trials of FNS and comparisons to other treatments for FM, and may provide a basis for investigating correlates and potential mechanisms of change. This program of research may contribute to immediate clinical applications to reduce FM symptoms and to better understanding of mechanisms of FM.